1. Technical Field
The present invention relates to a top coat paint exhibiting good rust resistance and good adhesion when formed into a coating film, a corrosion resistant surface-treated chain such as a bushed chain or a roller chain and a corrosion resistant surface-treated sprocket, for use in a corrosive atmosphere of brine, an acid, an alkali or the like on which a coating film is formed by using the top coat paint.
2. Description of Related Art
In order to prevent corrosion of a machinery such as a chain used in a corrosive atmosphere of brine, an acid, an alkali or the like, the surface of an iron base material of each component of the chain or the like was conventionally covered with a metal baser than iron such as zinc or covered with a metal nobler than iron such as nickel. Examples of the former zinc plating are electrogalvanizing and particle impact zinc plating, and examples of the latter nickel plating are nickel electroplating and electroless nickel plating.
Furthermore, a sacrificial corrosion preventive function of zinc and aluminum (a function to suppress corrosion of iron attained because such a metal has higher ionization tendency than iron and hence is eluted prior to iron) was utilized for forming a coating film on the surface of an iron base material of each component of the chain or the like by using a water-based rust preventive paint including zinc and aluminum as a metal pigment.
Japanese Patent No. 3122037 discloses an invention of an anticorrosive chain component in which a zinc film is formed on an iron base in a non-hydrogen atmosphere and a water-based rust preventive paint including an aluminum powder and a silicone resin is baking-finished so as to form a white rust inhibiting baked coating film.